Turbofan gas turbine engines typically have a segmented case assembly, mainly for weight reduction reasons, but also to facilitate fabrication and assembly. A conventional case assembly may include a fan case, an intermediate case, a gas generator case, a turbine case and a turbine exhaust case in serial arrangement about a center line of the engine. The gas generator case, turbine case and turbine exhaust case surround the hot section of the engine and are typically made of steel or nickel alloys, which have good thermal resistance properties. Steel is also conventionally used for the fan case because its strength is desirable for containing blade-off events. The intermediate case and the low compressor case which are part of cooler portions of the engine, conventionally employ lighter materials such as magnesium and aluminium. The outer ring of the intermediate case is usually provided with mount members to function as a mounting ring for connection with an aircraft to which the engine is mounted. Therefore, the structure of the intermediate case and thus the mounting ring, bear loads during engine operation and it is always a challenge to manufacture a low cost fabricated mounting ring for the intermediate case.
Accordingly, there is a need for an improved structure of a gas turbine engine mounting ring and a method of manufacturing such a mounting ring.